Data gathered by a non- profit organisation ICCT (International Council on Clean Transportation) reveals the growing disparity between the declared fuel consumption value by the car manufacturer and real fuel consumption of passenger cars under real world conditions. This gap is in addition to the defeat devices that some manufacturers had installed in their cars to manipulate exhaust emissions on a test stand. This brings up the important question as to whether data gathered from passenger cars emission tests have any value at all when one looks at the overall global carbon emissions.
Image Source: Statista
Image license: CC BY ND